1.0dev: Made the attachments directory upgrade a bit more admin-friendly, by moving stale files out of the way, and giving more detailed information on failures.
1.0dev: Made the attachments directory upgrade a bit more admin-friendly, by moving stale files out of the way, and giving more detailed information on failures.

Part of #10313.


git-svn-id: eda3d06fcef731589ace1b284159cead3416df9b@11162 af82e41b-90c4-0310-8c96-b1721e28e2e2

jun66j5/trac-ja,walty8/trac,jun66j5/trac-ja,walty8/trac,netjunki/trac-Pygit2,netjunki/trac-Pygit2,walty8/trac,jun66j5/trac-ja,netjunki/trac-Pygit2,walty8/trac,jun66j5/trac-ja